The heart is a hollow muscular organ with four pumping chambers: the left and right atria and the left and right ventricles. One-way valves between each of the chambers control the flow of blood in and out of the heart. The valves that control the blood flow between the atria and the ventricle are termed as Atrio-Ventricular Valves while the valves between the Ventricles and the outflow tracts are Outflow Tract/Semi-lunar Valves. The left atrio-ventricular valve is called the Mitral Valve, while the left ventricular outflow tract valve is called the Aortic Valve. Similarly, the right atrio-ventricular valve is called the Tricuspid Valve, while the right ventricular outflow tract valve is called the Pulmonary Valve. The atrioventricular valves, which are the mitral and tricuspid valves have four main components—the annulus which is a fibro-muscular ring, the leaflets which are planar collagenous tissues (2 in mitral, and 3 in tricuspid valves), several chordae tendineae that connect the leaflets to the papillary muscles. The mitral valve regulates blood flow between the left atrium and the left ventricle, while the tricuspid valve regulates flow between the right atrium and the right ventricle. The mitral valve consists of a D-shaped annulus with two leaflets emerging from it that extend into the left ventricle. Both the leaflets are connected via collagenous chordae tendineae to the tips of the anterolateral and posteromedial papillary muscles.
Similar to the mitral valve, the tricuspid valve, illustrated in FIG. 1, has an ovoid annular shape and regulates the flow of blood between the right atrium and the right ventricle. The tricuspid valve 10 has three main components—the tricuspid annulus 12, the three leaflets 14, 16, 18 and the three papillary muscles (not shown). The annulus 12 of the valve is a fibro-muscular ring from which the three leaflets 14, 16, 18 (anterior, septal and posterior) originate and regulate the flow through the valve orifice. The leaflets 14, 16, 18 extend inward into the valve or flow orifice defined by the annulus 12. There are three commissures between the three leaflets, which include an anteroseptal commissure 22, a posteroseptal commissure 24 and an anteroposterior commissure 26. Fibrous chordae tendineae extend from the three leaflets 14, 16, 18 and insert into the three papillary muscles extending from the heart muscle. The papillary muscles located in the right ventricle hold the leaflets and restrict them from collapsing into the right atrium. The tricuspid annulus 12 is an ovoid-shaped fibrous ring, which is not very prominent and is larger in the circumferential area and different in shape than the mitral valve.
Heart failure related to heart valve dysfunction is a widespread condition in which one or more of the heart valves fail to function properly. The dysfunction of the valves is mainly divided into two types: a) Valve Stenosis—wherein the effective flow orifice area of the valve is decreased due to various reasons and there is significant obstruction to the forward flow through the valve and b) Valve Incompetence—wherein the valves do not close properly and there is excessive retrograde leakage of blood when the valve is closed. Both types of these diseases have a debilitating effect on the performance of the heart and could also lead to congestive heart failure.
Surgery to repair damaged valves is the method of choice over valve replacement in the current surgical era. Surgical repair techniques involve reconstruction or controlled alteration of the geometry of the native valve using implantable devices. One of the most common repair technique used today by the surgeons to repair atrio-ventricular valve regurgitation is annuloplasty, in which, as illustrated in FIG. 2, the valve annulus 12 is geometrically stabilized or reduced in size by suturing onto the annulus 12 a prosthetic annuloplasty implant device, such as annuloplasty implant ring 30. As illustrated in FIG. 2, annuloplasty rings 12 are designed to roughly conform to the shape of the annulus 12 and maintain ample leaflet coaptation and allow good forward flow. There are also specific annuloplasty rings that have a non-physiological shape and upon implantation conform to the shape of the atrioventricular valve annulus to their non-physiological shape. These annuloplasty rings are generally made in different shapes, sizes and mechanical properties. D-shaped annuloplasty ring is the most common among the shapes with two important sub-categories being the full ring and a partial ring. The rings are also made rigid, semi-flexible and flexible that claim to allow the restoration of the native valve kinematics.
Implantation of these rings requires surgical intervention with an open-chest and the patient on cardiopulmonary bypass for a significant period. Surgical skill is of utmost importance in creating the sterna incision or thoracotomy and in opening the atrial wall to provide exposure of the valve. Due to its invasiveness and time on cardiopulmonary bypass, surgical repair of heart valves is a risky procedure and requires careful patient monitoring after the procedure. Thus, development of minimally invasive procedures to perform annuloplasty or to implant annuloplasty rings at the location of interest may decrease post-operative risk and reduce the patient mortality.
Present invention has particular relevance to the repair of dysfunctional atrioventricular valves using devices that enable minimally invasive implantation of annuloplasty rings and other devices thereof. The devices and techniques proposed in this application are intended to enable performing mitral annuloplasty through small incisions either in the right or left atria under image guidance either through ultrasound, fluoroscopy, magnetic resonance imaging or computer tomography. The technology allows for implantation of generic annuloplasty rings onto a multi-lumen catheter system for introduction and optimal alignment with the heart valve annulus, after which it is anchored to the surrounding tissue via needles, nitinol clips or sutures using a system of micro-electro-mechanical motors that can be operated from outside the patient's body.